Mukund D Rahalkar1, Anand M Rahalkar1, Dilip M Phadke2
1 Department of Radiology, Sahyadri Hospital, Pune, India
2 Department of Paediatrics, Sahyadri Hospital, Pune, India
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|Date of Web Publication ||6-May-2010 |
| Abstract || || |
Distal colostography (DC), also called distal colography or loopography, is an important step in the reparative management of anorectal malformations (ARMs) with imperforate anus, Hirschsprung's disease (occasionally) and colonic atresia (rarely) in children and obstructive disorders of the distal colon (colitis with stricture, carcinoma or complicated diverticulosis) in adults. It serves to identify/confirm the type of ARM, presence/absence of fistulae, leakage from anastomoses, or patency of the distal colon. We present a pictorial essay of DC in a variety of cases.
Keywords: Imperforate anus; imaging of anorectal malformations; pouch colon
|How to cite this article: |
Rahalkar MD, Rahalkar AM, Phadke DM. Pictorial essay: Distal colostography. Indian J Radiol Imaging 2010;20:122-5
| Introduction || || |
Distal colostography (DC) is an important diagnostic investigation to delineate the altered anatomy of anorectal malformations and know the spectrum of associated fistulae between the blind rectum on the one hand and the bladder, urethra, perineum and vagina on the other. It remains a dependable test for a surgeon to plan surgical repair.
| Discussion || || |
Anorectal malformations (ARMs) occur with an incidence of 1 in 5000  and their management is now well established, with immediate neonatal diverting colostomy in the high type of anomalies or anoplasty in the low type of anomalies.
About one month after colostomy or before the reparative surgery is planned, distal colostography (DC) is essential. It serves many purposes;  it helps the surgeon to:
According to Durham,  Keiller was the first to describe the DC technique of injecting barium sulphate to visualize the distal blind end. He advised washouts of the distal colon and removal of the accumulated meconium before injection of contrast. Later, along with others, Cremin , established the technique of DC in 1972. He insisted that the injection of contrast should be pressure-augmented. Gross  also stressed the value of the augmented pressure technique, where continued pressure is to be applied during injection to ensure that the fistula is opacified.
- Find the degree of fecal impaction and ectasia of the blind end of the rectum [Figure 1]. Prior information about the distended rectum helps the surgeon to plan the rectal pull-through surgery.
- Judge the distance of the blind rectum from the marker placed at the expected site of the anus (pouch-to-perineum distance)
- Detect precisely the various types of rectal fistulae , [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6] and [Figure 7], cloaca  [Figure 8] and pouch colon  [Figure 9].
The technique followed by us is as follows:
- A marker is placed over the anal dimple or expected position of the anus. Another marker is placed at the point where urine or fecal material is seen to be discharging.
- After passing an indwelling catheter through the stoma leading to the distal colon, its balloon is inflated and it is pulled back during injection of the contrast to avoid any spillage. The distal blind end of the colon gets filled progressively and pressure is maintained till the contrast fills the fistulous tract.
- Water-soluble contrast is used.
- Images are obtained under fluoroscopy.
- The colostogram is obtained in the lateral position, with the femora overlapping as perfectly as possible, to determine the level of the blind end of the rectum and identify the type of ARM.
In practice, DC is a very useful technique since it has a high specificity. Its sensitivity can be increased if proper care is taken to demonstrate the most distal end of the blind rectum and the fistula. 
Some surgeons perform a defunctioning colostomy for the management of the aganglionic colon. DC confirms the earlier diagnosis and helps in planning the further course of action [Figure 10].
Recto sigmoid obstructive disorders
In dealing with strictures due to chronic colitis or complicated diverticulosis and malignant tumors of the rectosigmoid region a defunctioning colostomy and resection with anastomosis are undertaken. DC is useful to check for any leakage from the site of anastomosis before closure of the colostomy [Figure 11].
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Mukund D Rahalkar
Radiology Department, Sahyadri Hospital, Plot No 30 C, Erandwane, Karve Road, Pune-411004
[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6], [Figure 7], [Figure 8], [Figure 9], [Figure 10], [Figure 11]